Pigmented malignant hidroacanthoma simplex mimicking irritated seborrheic keratosis

Malignant form of hidroacanthoma simplex: A case report

BACKGROUND

This paper presents a case of malignant hidroacanthoma simplex (HAS) and review the literature of previous cases to summarize the histopathological and immunohistochemical features and display the dermoscopic features of malignant HAS.

CASE SUMMARY

We present an 88-year-old Asian female with malignant HAS. The diagnosis was made according to the histopathological and immunohistochemical results after biopsy. Previous case reports of malignant HAS were retrieved from PubMed to characterize the histopathological and immunohistochemical features. We also display the dermoscopic features of malignant HAS that have not been reported.

CONCLUSION

Our findings demonstrate that prompt surgical treatment is an effective strategy for malignant HAS. Histopathology and immunohistochemistry are valuable diagnostic tools. This is the first case report to display the dermoscopic features of malignant HAS, and we speculate that dermoscopy may contribute to the diagnosis of malignant HAS.

A challenging case of pigmented Bowen's disease and differential diagnosis of pagetoid pigmented skin lesions

Differentiation of pagetoid cutaneous neoplasms can be very challenging on hematoxylin and eosin-stained sections.

We report a singular case of pigmented pagetoid Bowen’s disease showing transitional features between extramammary Paget’s disease and in situ squamous cell carcinoma.

Seborrheic keratosis: current concepts of pathogenesis

The article covers problems of seborrheic keratosis. The authors discuss current concepts of the etiology and pathogenesis of the disease paying special attention to the histology and immunohistochemistry of different forms and diverse clinical presentations. They describe Leser - Trelat syndrome as well as potential neoplastic transformation of seborrheic keratomas and their association with malignant skin neoplasms.

Poroma: a review of eccrine, apocrine, and malignant forms

Poroma is a benign adnexal neoplasm of the terminal sweat gland duct. Although poromas have traditionally been thought to originate from the eccrine sweat gland, there have been cases of apocrine etiology as well. Eccrine and apocrine poromas typically present as erythematous or flesh-colored nodules on the palms and soles. As these features overlap with a multitude of differential diagnoses, it is imperative to have a firm understanding of the characteristics that make the diagnosis of poroma. In addition, the malignant counterpart to the poroma, the eccrine porocarcinoma, manifests in a similar nonspecific fashion. Case studies and literature reviews have contributed immensely to our present knowledge of poroma and porocarcinoma. Given the rarity of these neoplasms, however, there remains a relative paucity of information on atypical presentations and rates of malignant transformation. In this article, the epidemiology, clinical presentation, diagnosis, and management of poroma and porocarcinoma will be reviewed. This systematic approach may serve as a guide in navigating the diagnostic dilemma of these rare cutaneous lesions.

Pigmented hidroacanthoma simplex: A diagnostic pitfall

Hidroacanthoma simplex (HAS) is a rare skin appendage tumor and is recognized as an intraepidermal variant of poroma. Pigmented HAS is an extremely rare variant with dendritic melanocytes and/or melanin pigment in the tumor cells and a few cases of pigmented HAS have been reported in the English literature. We herein report a case of pigmented HAS and discuss the clinicopathological features of pigmented HAS and the pitfall in the diagnosis of black lesions.

Melanocytic matricoma with melanocytic atypia: report of a unique case and review of the literature

Melanocytic matricoma is a rare cutaneous neoplasm of presumed anagen hair follicle origin with approximately 10 reported cases in the literature. Melanocytic matricomas are clinically and histopathologically distinct cutaneous nodular proliferations of matrical and supramatrical cells admixed with dendritic melanocytes, which typically occur in the sun-exposed areas of elderly patients. We report a new case with additional histopathologic features not previously described. An 82-year-old white man presented with an exophytic papule of the ear clinically suspicious for basal cell carcinoma. Histopathologic examination demonstrated a polypoid neoplasm consisting of an admixture of matrical and shadow cells with numerous interspersed dendritic and epithelioid melanocytes arranged singly and in large expansile nests. An unusual feature in this case included prominent melanocytic proliferation with associated nuclear atypia and increased mitotic activity. Although atypical and malignant melanocytic colonization has been reported in basal cell carcinomas and squamoproliferative lesions, to our knowledge, it has not been previously described in melanocytic matricomas. The biologic significance of atypical melanocytic proliferations within melanocytic matricomas is uncertain and requires further study of additional cases and long-term follow-up.

A case of porocarcinoma arising in pigmented hidroacanthoma simplex with multiple lymph node, liver and bone metastases

Porocarcinoma is a rare skin appendage carcinoma that may arise de novo or be associated with pre-existing poroma and hidroacanthoma simplex (HAS). Here, we report a case of porocarcinoma arising in pigmented HAS, which led to death from multiple lymph node, liver and bone metastases. A 72-year-old Japanese man presented with a brown to focal black flat plaque, measuring 17 × 12 mm, on the posterior region of his right thigh. Histopathological study of the tumor revealed that there was intraepidermal proliferation of small-sized basaloid cells, and it exhibited the 'Jadassohn phenomenon', with dendritic melanocytes, and a few ductal structures were observed. Continuing to the intraepidermal nests, the invasive proliferation of large polygonal cells with occasional intracytoplasmic ductal structures was observed. Carcinoembryonic antigen and epithelial membrane antigen were expressed in some carcinoma cells and they highlighted the intracytoplasmic ductal structures. Multiple lymph node, liver and bone metastases were observed, and the patient died 8 months after the initial surgery. Clinical diagnosis of HAS is extremely rare. Porocarcinoma may be associated with pre-existing HAS and sometimes shows aggressive behavior. Therefore, pigmented HAS must be included in the differential diagnosis of brown or black lesions. Ishida M, Hotta M, Kushima R, Okabe H. A case of porocarcinoma arising in pigmented hidroacanthoma simplex with multiple lymph node, liver and bone metastases.

Pigmented Squamous Cell Carcinoma

Although dendritic, melanin-containing melanocytes can be seen in a variety of epithelial neoplasms, only 0.01% to 7% of all squamous cell carcinomas (SCC) are pigmented. Furthermore, most reported cases have occurred in the oral and ocular mucosa, with relatively few cases reported to originate in the skin. Herein we report a case of a 61-year-old Caucasian male who presented with a large blue-black nodule on his left cheek, clinically suspicious for a melanoma; however, histological evaluation revealed an acantholytic pigmented squamous cell carcinoma. Previous cases are reviewed and the clinical and histological differential diagnoses are discussed.